1. Field of the Invention
The present invention relates to a multilayer ceramic electronic part to be embedded in a board and a printed circuit board having a multilayer ceramic electronic part embedded therein.
2. Description of the Related Art
As electronic circuits are highly dense and integrated, a mounting space for passive devices mounted on a printed circuit board may be insufficient. To solve this problem, an attempt to embed parts in the board, that is, to provide embedded devices, has been conducted. In particular, various methods of embedding a multilayer ceramic electronic part used as a capacitive part in a board have been proposed.
As methods of providing a multilayer ceramic electronic part within a board, there is provided a method of using a board material itself as a dielectric material for a multilayer ceramic electronic part and using copper wiring, or the like as an electrode for a multilayer ceramic electronic part. Further, as other methods of implementing an embedded multilayer ceramic electronic part, there are provided a method of forming an embedded multilayer ceramic electronic part by forming a high-K polymer sheet or a dielectric thin film in a board, a method of embedding a multilayer ceramic electronic part in a board, and the like.
Generally, a multilayer ceramic electronic part includes a plurality of dielectric layers formed of a ceramic material and internal electrodes inserted between the plurality of dielectric layers. Such a multilayer ceramic electronic part in the board is disposed within a board, thereby obtaining an embedded multilayer ceramic electronic part having high capacitance.
To manufacture a printed circuit board for a multilayer ceramic electronic part to be embedded therein, via holes need to be formed in an upper plate and a lower plate by using a laser, so as to connect board wirings to external electrodes of the multilayer ceramic electronic part after inserting the multilayer ceramic electronic part into a core board. Such laser processing is a factor in considerably increasing manufacturing costs of the printed circuit board.
Meanwhile, since the multilayer ceramic electronic part needs to be embedded in the core portion of the board, a nickel/tin (Ni/Sn) plating layer does not need to be formed on the external electrode, unlike in the case of a general multilayer ceramic electronic part mounted on a surface of a board.
That is, since the external electrode of the embedded multilayer ceramic electronic part is electrically connected to a circuit in the board through a via formed of copper (Cu), instead of through a nickel/tin (Si/Sn) layer, a copper (Cu) layer needs to be formed on the external electrode.
Generally, since even the external electrode is formed of copper (Cu) as a main component but also includes glass, the glass component absorbs the laser during laser processing for forming the via in the board, and thus, it may be difficult to adjust a depth of the via.
For this reason, such a copper (Cu) plating layer has been separately formed on the external electrode of the embedded multilayer ceramic electronic part.
However, due to the separately formed copper (Cu) plating layer, manufacturing costs may be increased, and due to the permeation of a plating solution, a problem in terms of reliability may still occur. Therefore, the above problems still need to be solved.